In the case of Batter X, you are talking anout one season worth of data broken down into small sample sizes. With post-season data, many look at it as one collective sample size of a few games spread out over many years.In Price's case, that means lumping in 2008 and 2009 in with 2016 as if they are all equally relevant. That's a long time ago, and not much is the same about Price is the same now as it was then. He's more experienced now, but also probably less fit. But typically the conclusion is "can't handle the pressure", which is sn insanely premature jump.
Of course Slasher's initial postulate was that Price was equal to Buchholz, which is laughable. Even if we ignore actual performance, Price gave the Sox over 200 IP last year, which has many positive effects. Buchholz didn't do that for Boston once in 10 seasons. And it's not like they were bad innings. Price was also excellent after a rough June. Sure he didn't deliver on some expectations that might have been unreasonable to begin with. But he was still very, very good with some room to grow.
And why the label of Price as a failure due to one post-season start and the subsequent coronation of Sale as the savior Price needed to be? Exactly what is it about Sale and his zero post-season starts that makes someone think he will fill this void?